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Why does solver "iterate" when using S() function?
Message #1 Posted by JamesT on 28 Sept 2011, 6:42 p.m.

Hi All,

I have a simple unit conversion formulas that I use on my HP17BII /HP17BII+ and decided to consolodate 3 of these into a single menu using the S() function. I have 2 nested IF(S(nnn)... functions, with a total of 3 equations:

LENGTH: IF(S(MM) OR S(INCH): MM * 0.03937007874 IN: IF(S(M) OR S(FEET):M * 3.280839895 FT : KM * 1.609344 - MILE))

The equation on the left most runs instantiously (mm-inch), while the two on the right iterate though the solution for some reason! On the 17BII, you get calculating, and the 17BII+ shows the min max iterations.

Run as stand-alone equations, they run instantly. Any ideas on how to fix this behavior?

      
Re: Why does solver "iterate" when using S() function?
Message #2 Posted by Don Shepherd on 28 Sept 2011, 8:35 p.m.,
in response to message #1 by JamesT

Shouldn't IN be INCH and FT be FEET in your formula? I think the KM/Mile conversion factor should be 0.621371192 (per Google anyhow).

The 17bii+ solver is going to use the iterative solver in situations where the 17b or 17bii solver would use the direct solver. I think Cyrille told me one time that that is due to memory constraints in the 17bii+. The 17bii does say CALCULATING but it derives a solution within a second or two; the plusses and the iterative solver take several seconds generally.

Edited: 28 Sept 2011, 8:50 p.m.

            
Re: Why does solver "iterate" when using S() function?
Message #3 Posted by JamesT on 28 Sept 2011, 9:37 p.m.,
in response to message #2 by Don Shepherd

You're right...I had fixed that after keying. The miles->km formula is calculating the reverse factor as it's keyed, so it works.

Disappointing that the plus is SO much slower than the older unit. Oh well. It does validate the equation faster, so not all is bad.


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